1. Field of the Invention
The present invention relates to an exhaust gas treatment device, in particular for an internal combustion engine, preferably in a motor vehicle.
2. The Prior Art
Exhaust gas treatment devices such as a catalytic converter or a particulate filter, in particular a soot filter, usually have a housing in which a suitable substrate body is arranged. The substrate body usually consists of a ceramic material, while the housing is made of sheet metal. Different thermal expansion coefficients result in extremely different thermal expansion properties of the housing and substrate body in operation of the exhaust gas treatment device. Accordingly, the substrate body cannot be mounted directly on the housing but instead must be secured via appropriate bearings in the housing. It is customary to use a radial bearing, in which a bearing mat made of a suitable bearing material surrounds the substrate body on the outside radially and supports it radially on the housing. This also results in an axial fixation and support of the substrate body on the housing by way of the bearing mat, i.e., by way of the radial bearing, due to an appropriately dimensioned radial compression of this bearing mat at the time of installation. Such a design has proven successful at least for catalytic converters.
In the case of particulate filters, in particular soot filters, a pressure drop which occurs in flow through the substrate body is much greater than the pressure drop with a substrate body of a traditional catalytic converter. Accordingly, the axial forces acting on the substrate body of a particulate filter (pressure difference at the axial end faces, frictional forces of the gas flow) are much greater than those with a traditional catalytic converter.